Members of the Armed Forces Full Honor Cordon from the Military District of Washington roll up the red carpet after a practice run for the arrival of Pope Francis. (AP Photo/Susan Walsh)
Pope Francis waves upon his arrival at Andrews Air Force Base, Md., Tuesday, Sept. 22, 2015, where President, Mrs. Obama, and others were to greet him. (AP Photo/Andrew Harnik)
Pope Francis walks down the steps of his plane upon his arrival at Andrews Air Force Base, Md., Tuesday, Sept. 22, 2015, where President Barack Obama was to greet him. (AP Photo/Andrew Harnik)
President Barack Obama and first lady Michelle Obama greet Pope Francis upon his arrival at Andrews Air Force Base, Md., Tuesday, Sept. 22, 2015. (AP Photo/Andrew Harnik)
Pope Francis talks with President Barack Obama, accompanied by first lady Michelle Obama, after arriving at Andrews Air Force Base in Md., Tuesday, Sept. 22, 2015. (AP Photo/Susan Walsh)
Pope Francis, accompanied by President Barack Obama, and others, is greeted upon his arrival at Andrews Air Force Base, Md., Tuesday, Sept. 22, 2015. (AP Photo/Andrew Harnik)
The pope will be riding in a Fiat 500L. (ABC News)
Pope Francis waves from a Fiat 500L as his motorcade departs Andrews Air Force Base, Md., Tuesday, Sept. 22, 2015, after being greeted by President Barack Obama. (AP Photo/Andrew Harnik)
Pope Francis arrived Tuesday afternoon in Washington D.C. for the first leg of his trip to the United States.